Refrigerated cargo containers, such as, for example, those defined or present within refrigerated trucks, refrigerated trailers, refrigerated railroad cars, or the like, are conventionally used, for example, to house or store, and effectively maintain frozen or refrigerated, perishable cargo, while such perishable cargo is being transported in connection with its commercial distribution, in order to preserve such perishable cargo in its freshest possible condition or state. The refrigeration units are conventionally mounted within the forward end portions of the cargo containers, such as, for example, upon the front walls of the cargo containers. In accordance with conventional cooling processes, cycles, or methodology, cooled or conditioned air is discharged or exhausted from the refrigeration unit outlet, which is disposed within the upper region of the cargo container, such that the air is effectively conducted in the rearward direction and through the cargo container within the vicinity of the cargo container ceiling. At the same time, warmer air is drawn in the forward direction, through the lower region of the cargo container within the vicinity of the cargo container floor structure, so as to effectively be conducted or routed back toward, and into, the refrigeration unit inlet. Such return air is then able to be re-cooled or re-conditioned for recirculation back into the cargo container as a result of again being exhausted or discharged from the refrigeration unit outlet.
In order to properly facilitate or establish the aforenoted air flow patterns within the refrigerated cargo containers, one type of bulkhead structure that has been conventionally installed within refrigerated cargo containers comprises air return bulkhead structures which are disposed in spaced relationship with respect to the front walls of the refrigerated cargo containers so as to effectively define plenum chambers or spaces into which the warmer return air can be effectively be conducted back toward the refrigeration unit inlet. More particularly, the air return bulkhead structures, in addition to effectively defining the aforenoted plenum space or chamber, also serve to effectively protect the refrigeration units from being damaged, such as, for example, by means of the cargo loads which may tend to shift in place during the transportation of the same. Conventional air return bulkhead structures, of the aforenoted type, are disclosed, for example, within U.S. Pat. No. 6,203,419 which issued to Onken on Mar. 20, 2001, U.S. Pat. No. 6,116,044 which issued to Gothier on Sep. 12, 2000, U.S. Pat. No. 5,993,310 which issued to Onken on Nov. 30, 1999, U.S. Pat. No. 5,947,812 which issued to Henning et al. on Sep. 7, 1999, U.S. Pat. No. 5,807,046 which issued to Onken on Sep. 15, 1998, and U.S. Pat. No. 5,769,704 which issued to Henning et al. on Jun. 23, 1998. While all of the aforenoted air return bulkhead structures are constructed so as to achieve or perform their predetermined objectives in a substantially satisfactory or adequate manner, it is noted that such air return bulkhead structures do not comprise, in effect, thermal barriers which are required for defining separate freezer, refrigerated, and dry compartments within the refrigerated cargo container.
Accordingly, a second type of bulkhead structure that has conventionally been incorporated within refrigerated cargo containers is a thermal barrier type bulkhead structure, however, it is known that such conventional PRIOR ART thermal barrier type bulkhead structures have inherent operational, installation, and manufacturing drawbacks or disadvantages. For example, it is known in the art or industry that different cargo containers, as defined within differently sized trucks, trailers, railroad cars, or the like, are characterized by different internal width and height dimensions. It can therefore be readily appreciated that when a thermal barrier type bulkhead structure is to be internally incorporated within a particular refrigerated cargo container, it must obviously be manufactured or fabricated in accordance with predeterminedly precise dimensional specifications. It can be further readily appreciated, however, that such manufacturing or fabrication processing is very costly, such manufacturing or fabrication processing requires a substantial lead-time in order to achieve the manufacture or fabrication of the thermal bulkhead structure, and lastly, such manufacturing or fabrication processing results in a correspondingly long delivery time of the bulkhead structure to the end customer. While it is noted that the various air return bulkhead structures, as disclosed, for example, within the aforenoted patents which issued to Onken, do comprise upper support panels which are provided with ridges or other discontinuities along which a cutting tool may be guided so as to effectively form different spaces for accommodating differently sized refrigeration units, and while, still further, other structural components or parts of the air return bulkhead structures may likewise be removed so as to alter the return airflow patterns leading back to the refrigeration unit inlet, the provision and use of such severable structural components or parts nevertheless do not address the aforenoted problem concerning the requirement or need for providing individual, precisely sized thermal bulkhead structures which are to be internally incorporated within the differently sized refrigerated cargo containers. More particularly, it is noted that the air return bulkhead structures, as disclosed, for example, within the aforenoted patents which issued to Onken, are not capable of having their dimensional sizes expanded or contracted so as to effectively be used in a properly sealed manner with respect to the internal wall members of the differently sized refrigerated cargo containers which define the internal cargo container space within the refrigerated cargo containers.
A need therefore exists in the art for a new and improved thermal type bulkhead structure for incorporation within differently sized refrigerated cargo containers, such as, for example, those defined or present within refrigerated trucks, refrigerated trailers, refrigerated railroad cars, and the like, wherein the new and improved thermal type bulkhead structure can be readily and easily expanded and contracted so as to effectively alter the height and width dimensions of the thermal type bulkhead structure in order to permit the thermal type bulkhead structure to be utilized within differently sized refrigerated cargo containers in a properly sealed manner with respect to the internal wall members of the differently sized refrigerated cargo containers which define the internal cargo container space within the refrigerated cargo container. In this manner, the thermal type bulkhead structure can effectively comprise a single, universal thermal type bulkhead structure which could effectively be mass-produced and subsequently installed in an onsite manner within any particularly sized or dimensioned refrigerated cargo container so as to respectively define freezer, refrigerated, and dry compartments within the refrigerated cargo container. As a result of the provision of such a universal thermal type bulkhead structure, the need to manufacture or fabricate a multitude of differently sized or dimensioned thermal type bulkhead structures, in accordance with predetermined size dimensions characteristic of different, predetermined or specific refrigerated cargo containers, would be obviated, rendered unnecessary, and eliminated.